Method and device for detecting touch pad unit
A method and system for detecting the presence of an object at a touch pad device, wherein the touch pad device has a designated interaction area for allowing a user to use the object to interact with the touch pad device for inputting one or more functions in an electronic device. One or more groups of optical sensor components, each including an optical receiver and two light emitters positioned at opposite sides of the receiver such that when an object is present at the touch pad device, the changes in the receiver output can be used to determine the location of the object as a function of time. Preferably, the light emitters are operated in a pulsed mode so that the changes in the receiver output contain a frequency component so as to distinguish the changes due to the presence of the object and those of ambient light.
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Reference is made to pending application Ser. No. 09/928,929 entitled METHOD AND SYSTEM FOR PREVENTING UNINTENDED TOUCH PAD INPUT DUE TO ACCIDENTAL TOUCHING, assigned to the assignee of the present invention and filed on even date herewith.
FIELD OF THE INVENTIONThe present invention relates generally to a touch sensitive device in an electronic device or a wireless telecommunication terminal.
BACKGROUND OF THE INVENTIONA touch pad is usually defined as a touch-sensitive user interface area in an electronic device, which allows a user to input information or a command to the device by pressing the touch sensitive area. The touch pad can be used as a keypad having a designated functionality. For example, a touch pad can be used as an on/off switch and the user can turn the electronic device on or off by pressing the touch sensitive area. The touch pad can have several selectable functions. For example, the touch pad can be used as a keyboard having a plurality of soft-keys of different functions to allow the user to enter or select one function at a time.
In some touch pads, it is required to press the pad surface in order to deform it. In such a touch pad, several layers of material, separated by thin spacers, are used to form a grid of vertical and horizontal rows of electrodes. An electrical current is maintained in the grid of electrodes. When a user presses the pad, the layers are caused to make contact with each other at the pressing point, thereby interrupting the current in the electrode grid. A detection circuit is used to detect the interruption in the current and determine the location of the pressing point on the pad. In other touch pads, mere touching of the pad surface by a finger is sufficient. This latter type of touch pad can be of a resistive-type or capacitive-type. On a resistive-type touch pad, a thin, electrically conductive and resistive layer is coated on the surface of the touch pad area. On a capacitive-type touch pad, a coated layer forming a matrix of pixel-like capacitors is provided on the touch sensitive area. When a finger touches the surface, it changes the electrical characteristics of the coated layer. By measuring the resistance or capacitance values at a number of surface points corresponding to the pressing point, the location of the pressing point can be determined. On an inductive-type touch pad, inductive elements are distributed over the touch pad area. A stylus made of an inductive material is used to change the signals transmitted through the inductive elements for the detection of the presence of the stylus. In some touch pads, if the user moves the touching object around the touch sensitive area and a series of pressing points are registered, the movement of the touching object can also be calculated.
When the touch pad is also used as an information display or an image display, the electrodes positioned on top of a touch pad may affect the optical transparency of display and/or distort the displayed text or image. Furthermore, some touch pads can be damaged by having dirt or scratches on the touch pad surface. In recent years, surface wave technology is also used in touch pad applications. In particular, ultrasonic waves propagating on the touch pad surface are used to detect the interruption or absorption of the waves due to touching. While a touch pad using this surface wave technology does not affect the optical quality of the display, it is costly to produce.
It is advantageous and desirable to provide a touch pad, which is cost effective and does not affect its optical quality.
SUMMARY OF THE INVENTIONAccording to the first aspect of the present invention, a method of sensing and detecting the presence of an object at a touch pad device having one or more input functions, wherein the touch pad device has a designated interaction area for allowing a user to use the object to interact with the touch pad device to facilitate the input of touch pad functions, said method comprising the steps of:
providing at least one group of optical sensor components including a first light emitter, a second light emitter and a light receiver in the touch pad device at different locations thereof such that the receiver is capable of receiving a first amount of light emitted by the first light emitter and a second amount of light emitted by the second light emitter; wherein when the object is present at the touch pad device, causes a change in the first amount of light and the second amount of light;
measuring separately the change in the first amount of light and the change in the second amount of light for providing a first signal and a second signal indicative of the respective changes; and
determining the location of the object in the designated interaction area in relation to the first light emitter and the second light emitter based on the first and second signals.
It is preferable that the first and second emitters are operated in a pulsed mode of a predetermined frequency so that the changes in the first amount of light and second amount of light contain a frequency component so as to distinguish the changes in the first amount of light and second amount of light due to the presence of the object over the changes due to ambient light.
It is further preferable to provide a compensation emitter, which is placed adjacent to the receiver and operated in a pulsed mode of the same frequency, but with a complementary phase regarding the first and second emitters, so as to reduce the effect of the surface condition of the touch pad device on the changes in the first amount of light and second amount of light.
It is also preferable to provide a second group of similar optical sensor components in the touch pad device placed at different locations for further determining the location of the object in the designated interaction area in relation to light emitters in the second group of optical sensor components. The optical sensor components can be placed within the designated interaction area or outside the designated interaction area.
According to the second aspect of the present invention, a touch pad device to be used in conjunction with a measurement device, the touch pad device having a designated interaction area for sensing and detecting the presence of an object at the designated interaction area, said touch pad device comprising:
a light receiver provided in or near the designated interaction area, and
a first light emitter and a second light emitter provided respectively at a first location and a second different location in the designated interaction such that the receiver is capable of receiving a first amount of light emitted by the first light emitter and a second amount of light emitted by the second light emitter, wherein when the object is present at the touch pad device, causes a change in the first amount of light and the second amount of light, the change in the first amount of light and the change in the second amount of light being separately measured by the measurement device for determining the location of the object in the designated interaction area in relation to the first light emitter and the second light emitter based on the first and second signals.
It is preferable that the first and second emitters are operated in a pulsed mode of a predetermined frequency so that the changes in the first amount of light and second amount of light contain a frequency component so as to distinguish the changes in the first amount of light and second amount of light due to the presence of the object over the changes due to ambient light.
It is further preferable to provide a compensation emitter, which is placed adjacent to the receiver and operated in a pulsed mode of the same frequency, but with a complementary phase regarding the first and second emitter, so as to reduce the effect of the surface condition of the touch pad device on the changes in the first amount of light and second amount of light.
It is also preferable that the touch pad device further comprises a second group of similar optical sensor components placed in or near the designated interaction area at different locations from the locations of the first and second light emitters and the receiver for further determining the location of the object in the designated interaction area in relation to light emitters in the second group of optical sensor components. The optical sensor components can be placed inside the designated interaction area or outside the designated interaction area.
According to the third aspect of the present invention, a system for sensing and detecting the presence of an object at a touch pad device, wherein the touch pad device has a designated interaction area for allowing a user to use the object to interact with the touch pad device, said system comprising:
at least one group of optical sensor components including a first light emitter, a second light emitter and a light receiver in the touch pad device at different locations thereof such that the receiver is capable of receiving a first amount of light emitted by the first light emitter and a second amount of light emitted by the second light emitter, wherein the first amount of light and the second amount of light are caused to change when the object is present at the touch pad device;
means, operatively connected to the light receiver, for separately measuring the change in the first amount of light and the change in the second amount of light for providing a first signal and a second signal indicative of the respective changes; and
means, responsive to the first signal and second signal, for determining the location of the object in the designated interaction area in relation to the first light emitter and the second light emitter based on the first and second signals.
It is preferable that the first and second emitters are operated in a pulsed mode of a predetermined frequency so that the changes in the first amount of light and second amount of light contain a frequency component so as to distinguish the changes in the first amount of light and second amount of light due to the presence of the object over the changes due to ambient light.
It is further preferable to provide a compensation emitter, which is placed adjacent to the receiver and operated in a pulsed mode of the same frequency, but with a complementary phase regarding the first and second emitter, so as to reduce the effect of the surface condition of the touch pad device on the changes in the first amount of light and second amount of light.
It is also preferable to provide a second group of similar optical sensor components in the touch pad device placed at different locations for further determining the location of the object in the designated interaction area in relation to light emitters in the second group of optical sensor components.
The present invention will become apparent upon reading
As shown in
The touch pad device 1 can have a single input functionality or multiple input functionality. For example, the touch pad device 1 can be used as an “enter” key in a keyboard, as shown in
In
It should be noted that with the arrangement of optical sensor components, as shown in
In
With four emitters 10, 12, 20, 22 and two receivers 30, 32, it is preferred that a series of measurements, each using a different emitter/receiver pair, be carried out to determine the location of the touching point. For example, the measurement result from the emitter 10 and receiver 30 pair (
As can be seen in TABLE I, only one emitter and one receiver are used, or enabled, for measurement at a time. All the other sensor elements are disabled or not used. The enabling and disabling of the optical sensor components is carried out by a timing control module, as shown in FIG. 14. If the turn-on time is one millisecond for each measurement cycle, it will take only eight milliseconds to complete all the measurement cycles. It is understood that one series of eight measurement cycles can be used to determine the-two dimensional coordinates of the touching point with respect to the touch pad area 5. By repeating the same series, the movement of the approaching object can also be tracked.
Optionally, the output from two emitters can be combined in a single measurement. For example, the measurement result from the emitters 10, 22 and the receiver 30 (
Four groups of sensor components can be placed on four sides of the touch pad area 5, as shown in
Alternatively, all the emitters 10, 12, 14, 16, 20, 22, 24 and 26 are operated in a pulsed mode of a predetermined frequency. However, the emitters 10, 20, 12 and 22 are operated in a phase complementary of the phase of the emitters 14, 24, 16 and 26. As such, a measurement of the horizontal position can be made simultaneously with a measurement of the vertical position in order to reduce the measurement time.
It is also possible that the operating wavelength of the sensor components 14, 16, 24, 26, 34 and 36 is different from the operating wavelength of the sensor components 10, 12, 20, 22, 30 and 32. In that case, two measurements of different wavelengths can be made simultaneously. For example, the measurement taken with the emitter 10 and the receiver 30 can be carried out simultaneously with the measurement taken with the emitter 14 and the receiver 34. With two wavelengths, the measurement time can be reduced in half.
Alternatively, two emitters at each corner can be replaced by a bi-wavelength emitter, as shown in
In a mobile device or other electronic device, the touch pad area 5 can be a display panel such as a liquid crystal display (LCD) 92 mounted on a printed circuit board (PCB) or a printed wire board (PWB) 90. As shown in
In the embodiments, as illustrated in
The emitters 10, 11, 12, 13, 14, 16, 20, 21, 22, 23, 24 and 26, as described herein, can be operated in a continuous mode in that the output of the emitters does not contain a high frequency component, similar to the output of an incandescent lamp. Accordingly, the output signal 130 (
It should be noted that the output signal of the receiver 30 attributable to a pulsed emitter 10 arranged in a touch pad device, such as that illustrated in
Best Mode
In order to use the above-mentioned phase compensation technique, it is preferred that adjacent to each of the receivers 30, 32, 34, 36, as shown in
Preferably, the light emitters 10, 12, 14, 16, 20, 22, 24 and 26 are light-emitting diodes (LEDs) operated in an infrared (IR) or far-IR frequency range.
Alternative Embodiments
The optical sensor components, as shown in
I. A(t), B(t), C(r), D(c)
II. A(t), B(t), C(c), D(r)
III A(r), B(c), C(t), D(t)
IV A(c), B(r), C(t), D(t)
As such, the combination of (I+II) yields a first horizontal position; the combination of (III+IV) yields a second horizontal position; (I+II)−((III+IV) yields the vertical position; and (I+II)+(III+IV) yields the horizontal position. For a sufficient large touch pad area, it is desirable to further include the following measurements:
V. A(t), B(r), C(c), D(t)
VI. A(t), B(c), C(r), D(t)
VII. A(r), B(t), C(t), D(c)
VIII. A(c), B(t), C(t), D(r)
As such, the combination of (V+VI) yields a first vertical position; (VII+VIII) yields a second vertical position; and (V+VI)+(VII+VIII) yields the vertical position.
The measurements regarding the arrangements, as shown in
The touch pad device 1, according to the present invention, has many applications. The touch pad device 1 can be used as a key in a keyboard, as illustrated in
Instead of being rectangular, the touch pad area can be round, elliptical, polygonal or of a irregular shape.
It should be noted that the transmission and reflection of light, as depicted in the drawings, is for illustrative purposes only. For example, the light rays shown in
The present invention provides a method and device for detecting and sensing the presence of a touching object and the movement thereof in or near a touch pad area. The touch pad device 1, as depicted in
In the embodiments, as depicted in
It is preferred the optical sensor components are solid state devices such as light-emitting diodes, optoelectronic sensors and transceivers operated at IR or far-IR frequencies. However, optical sensor components operated at other frequencies can also be used.
Thus, although the invention has been described with respect to a preferred embodiment thereof, it will be understood by those skilled in the art that the foregoing and various other changes, omissions and deviations in the form and detail thereof may be made without departing from the spirit and scope of this invention.
Claims
1. A method of sensing and detecting the presence of an object at a touch pad device having one or more input functions, wherein the touch pad device has a designated interaction area for allowing a user to use the object to interact with the touch pad device for activating said one or more input functions depending on a location of the object, the designated interaction area having a periphery, and wherein the touch pad device has a surrounding area substantially surrounding the periphery of the designated interaction area, said method comprising the steps of:
- providing in the surrounding area at least one group of optical sensor components including a first light emitter, a second light emitter and a light receiver in the touch pad device at different locations thereof such that the receiver is capable of receiving a first amount of light emitted by the first light emitter and reflected by the object and a second amount of light emitted by the second light emitter and reflected by the object; wherein when the object is present at the touch pad device, causing a change in the first amount of light and the second amount of light,
- measuring separately the change in the first amount of light and the change in the second amount of light for providing a first signal and a second signal indicative of the respective changes; and
- determining the location of the object in the designated interaction area in relation to the first light emitter and the second light emitter by comparing the change in the first amount of light and the change in the second amount of light based on the first and second signals, wherein the change in the first amount of light and the second amount of light is an increased amount when the object is present at the touch pad device.
2. The method of claim 1, wherein the measuring and determining steps are carried repeatedly for providing changes in the location of the object as a function of time.
3. The method of claim 1, wherein the designated interaction area has an upper side and a lower side, and said group of optical sensor components is placed on either the upper side or the lower side.
4. The method of claim 1, wherein the designated interaction area has a left side and a right side, and said group of optical sensor components is placed on either the left side or the right side.
5. The method of claim 1, wherein the first and second light emitters are operated in a pulsed mode of a predetermined frequency so that the changes in the first amount of light and the second amount of light contain a frequency component of the predetermined frequency.
6. The method of claim 1, wherein the touch pad device further includes a further group of optical sensor components including a third light emitter, a fourth light emitter and a further light receiver in the touch pad device at different locations thereof separating said first and second light emitters and the light receiver such that the further receiver is capable of receiving a third amount of light emitted by the third light emitter and a fourth amount of light emitted by the fourth light emitter; wherein when the object is present at the touch pad device, causing a change in the third amount of light and the fourth amount of light said method further comprising the steps of:
- measuring separately the change in the third amount of light and the change in the fourth amount of light for providing a third signal and a fourth signal indicative of the respective changes; and
- determining the location of the object in the designated interaction area in relation to the third light emitter and the fourth light emitter based on the third and fourth signals.
7. The method of claim 6, wherein the designated interaction area has an upper side and a lower side, and wherein said group of optical sensor components is placed at the upper side and said further group of optical sensor components is placed at the lower side.
8. The method of claim 6, wherein the designated interaction area has a left side and a right side, and wherein said group of optical sensor components is placed at the left side and said further group of optical sensor components is placed at the right side.
9. The method of claim 6, wherein the first, second, third and fourth light emitters are operated in a pulsed mode of a predetermined frequency so that the changes in the first amount, the second amount, the third amount and the fourth amount of light contain a frequency component of the predetermined frequency.
10. The method of claim 6, wherein the measuring steps regarding the first amount, second amount, third amount and fourth amount of light and the determining steps based on the first signal, the second signal, the third signal and the fourth signal are carried out repeatedly for providing changes in the location of the object as a function of time.
11. The method of claim 1, wherein the touch pad device has a display screen disposed in the inner area for showing said one or more input functions.
12. A touch pad device to be used in conjunction with a measurement device, wherein the touch pad device has a designated interaction area for allowing a user to use an object to interact with the designated interaction area in order to activate one or more functions associated with the touch pad device dependent on a location of the object, the designated interaction area having a periphery wherein the touch pad device also has a surrounding area substantially surrounding the periphery of the designated interaction area, said touch pad device comprising:
- a light receiver provided in the surrounding area, and a first light emitter and a second light emitter provided respectively at a first location and a second different location in the surrounding area in relationship to the light receiver such that the light receiver is capable of receiving a first amount of light emitted by the first light emitter and reflected by the object, and a second amount of light emitted by the second light emitter and reflected by the object, wherein when the object is present at the touch pad device, it causes a change in the first amount of light and the second amount of light, and wherein the change in the first amount of light and the change in the second amount of light are separately measured by the measurement device and these measured changes are compared for determining the location of the object in the designated interaction area in relation to the first light emitter and the second light emitter, wherein the change in the first amount of light and the second amount of light is an increased amount when the object is present at the touch pad device.
13. The touch pad device of claim 12, wherein the first and second light emitters are operated in a pulsed mode of a predetermined frequency so that the changes in the first amount of light and the second amount of light contain a frequency component of the predetermined frequency.
14. The touch pad device of claim 12, wherein the light emitters are light-emitting diodes.
15. The touch pad device of claim 12, wherein the light emitters are operated in an infrared frequency range.
16. The touch pad device of claim 12, wherein the designated interaction area has an upper side and a lower side and the first light emitter, the second light emitter and the light receiver are provided at the upper side, said touch pad device further comprising:
- a further light receiver provided at the lower side;
- a third light emitter provided at a third location adjacent the light receiver; and
- a fourth light emitter provided at a fourth location adjacent the light receiver different from the third location such that the further light receiver is capable of receiving a third amount of light emitted by the third light emitter and a fourth amount of light emitted by the fourth light emitter, wherein when the object is present at the touch pad device, causes a change in the third amount of light and the fourth of light, the change in the third amount of light and the change in the fourth amount of light being separately measured by the measurement device for further determining the location of the object in the designated interaction area in relation to the third light emitter and the fourth light emitter.
17. The touch pad device of claim 12, wherein the designated interaction area has a left side and a right side and the first light emitter, the second light emitter and the light receiver are provided at the left side, said touch pad device further comprising:
- a further light receiver provided at the right side;
- a third light emitter provided at a third location adjacent the light receiver; and
- a fourth light emitter provided at a fourth location adjacent the light receiver different from the third location such that the further light receiver is capable of receiving a third amount of light emitted by the third light emitter and a fourth amount of light emitted by the fourth light emitter, wherein when the object is present at the touch pad device, causes a change in the third amount of light and the fourth of light, the change in the third amount of light and the change in the fourth amount of light being separately measured by the measurement device for further determining the location of the object in the designated interaction area in relation to the third light emitter and the fourth light emitter.
18. The touch pad device of claim 12, wherein the inner area has a display screen for showing said one or more functions.
19. The touch pad device of claim 18, wherein the display screen comprises an LCD.
20. A system for sensing and detecting the presence of an object at a touch pad device, wherein the touch pad device has a designated interaction area for allowing a user to use the object to interact with the touch pad device in order to activate one or more functions associated with the touch pad device, the designated area having a periphery, and wherein the touch pad device also has a surrounding area substantially surrounding the periphery of the designated interaction area, said system comprising:
- at least one group of optical sensor components including a first light emitter, a second light emitter and a light receiver in the surrounding area at different locations thereof such that the light receiver is capable of receiving a first amount of light emitted by the first light emitter and reflected by the object, and a second amount of light emitted by the second light emitter and reflected by the object, wherein the first amount of light and the second amount of light are caused to change when the object is present at the touch pad device;
- a measurement module, operatively connected to the light receiver, for separately measuring the change in the first amount of light and the change in the second amount of light for providing a first signal and a second signal indicative of the respective changes so as to determine the location of the object in the designated interaction area in relation to the first light emitter and the second light emitter by comparing the first and second signals, wherein the change in the first amount of light and the second amount of light is an increased amount when the object is present at the touch pad device.
21. The system of claim 20, wherein the measurement module comprises a timing control module for disabling the first light emitter when the change in the second light amount is measured and disabling the second light emitter when the change in the first light amount is measured.
22. The system of claim 20, wherein the first light emitter and the second light emitter are operated in a pulsed mode of a predetermined frequency so that the changes in the first amount and the second amount contain a frequency component of the predetermined frequency, and wherein the measurement module further comprises a filtering module for providing the frequency component.
23. A method of sensing and detecting the presence of an object at a touch pad device having one or more input functions, wherein the touch pad device has a designated interaction area for allowing a user to use the object to interact with the touch pad device for performing said one or more input functions, said method comprising the steps of:
- providing at least one group of optical sensor components including a first light emitter, a second light emitter and a light receiver in the touch pad device at different locations thereof such that the receiver is capable of receiving a first amount of light emitted by the first light emitter and a second amount of light emitted by the second light emitter; wherein when the object is present at the touch pad device, causing a change in the first amount of light and the second amount of light,
- measuring separately the change in the first amount of light and the change in the second amount of light for providing a first signal and a second signal indicative of the respective changes; and
- determining the location of the object in the designated interaction area in relation to the first light emitter and the second light emitter based on the first and second signals, wherein the first and second light emitters are operated in a pulsed mode of a predetermined frequency so that the changes in the first amount of light and the second amount of light contain a frequency component of the predetermined frequency, and wherein the pulsed mode of the first and second light emitters are operated in a pulsed mode of a predetermined frequency with a first phase and said group of optical sensor components further includes a third light emitter positioned adjacent to the light emitter to provide a third amount of light to the light receiver, and wherein the third light emitter is operated in said pulsed mode with a second phase complementary of the first phase and the third light emitter is controlled such that the third amount of light is substantially equal to a sum of the first amount and the second amount when the object is not present at the touch pad device so as to reduce a frequency component in the sum of the first, second and third amounts.
24. A method of sensing and detecting the presence of an object at a touch pad device having one or more input functions, wherein the touch pad device has a designated interaction area for allowing a user to use the object to interact with the touch pad device for performing said one or more input functions, said method comprising the steps of:
- providing at least one group of optical sensor components including a first light emitter, a second light emitter and a light receiver in the touch pad device at different locations thereof such that the receiver is capable of receiving a first amount of light emitted by the first light emitter and a second amount of light emitted by the second light emitter; wherein when the object is present at the touch pad device, causing a change in the first amount of light and the second amount of light,
- measuring separately the change in the first amount of light and the change in the second amount of light for providing a first signal and a second signal indicative of the respective changes; and
- determining the location of the object in the designated interaction area in relation to the first light emitter and the second light emitter based on the first and second signals, wherein the touch pad device further includes a further group of optical sensor components including a third light emitter, a fourth light emitter and a further light receiver in the touch pad device at different locations thereof separating said first and second light emitters and the light receiver such that the further receiver is capable of receiving a third amount of light emitted by the third light emitter and a fourth amount of light emitted by the fourth light emitter; wherein when the object is present at the touch pad device, causing a change in the third amount of light and the fourth amount of light said method further comprising the steps of:
- measuring separately the change in the third amount of light and the change in the fourth amount of light for providing a third signal and a fourth signal indicative of the respective changes; and
- determining the location of the object in the designated interaction area in relation to the third light emitter and the fourth light emitter based on the third and fourth signals, wherein the first, second, third and fourth light emitters are operated in a pulsed mode of a predetermined frequency so that the changes in the first amount, the second amount, the third amount and the fourth amount of light contain a frequency component of the predetermined frequency, and wherein the pulsed mode of the first, the second, the third and the fourth light emitters has a first phase, and wherein said group of optical sensor components further includes a first compensation light emitter positioned adjacent to the light receiver to provide a first compensation amount of light to the light receiver, and said further group of optical sensor components further includes a second compensation light emitter positioned adjacent to the further light receiver to provide a second compensation amount to the further light receiver, and the first and second compensation light emitters are operated in a further pulsed mode of the predetermined frequency having a second phase complementary of the first phase and the first and the second compensation light emitters are controlled such that the first compensation amount of light is substantially equal to a sum of the first amount and the second amount, and the second compensation amount of light is substantially equal to a sum of the third amount and the fourth amount when the object is not present at the touch pad device.
25. A touch pad device to be used in conjunction with a measurement device, the touch pad device having a designated interaction area for sensing and detecting the presence of an object at the designated interaction area, said touch pad device comprising:
- a light receiver provided in or near the designated interaction area, and a first light emitter and a second light emitter provided respectively at a first location and a second different location in the designated interaction area such that the light receiver is capable of receiving a first amount of light emitted by the first light emitter and a second amount of light emitted by the second light emitter, wherein when the object is present at the touch pad device, causes a change in the first amount of light and the second amount of light, the change in the first amount of light and the change in the second amount of light being separately measured for determining the location of the object in the designated interaction area in relation to the first light emitter and the second light emitter, and wherein the designated interaction area has an upper right corner, an upper left corner, a lower right corner and a lower left corner, and
- the first light emitter is provided at the upper right corner;
- the second light emitter is provided at the upper left corner; and
- the light receiver are positioned between the first and second light emitters, said touch pad device further comprising:
- a third light emitter provided at the lower right corner;
- a fourth light emitter provided at the lower left corner;
- a second light receiver positioned between the third and fourth light emitters, and wherein the second light receiver is capable of receiving a third amount of light emitted by the third light emitter and a fourth amount of light emitted by the fourth light emitter for further determining the location of the object in the designated interaction area in relation to the third light emitter and the fourth light emitter based separately on a change in the third amount and the fourth amount, wherein the first, second, third and fourth light emitters are bi-wavelength emitters emitting light at a first wavelength and a second wavelength, and the light receiver and the second light receiver are receivers operated at the first wavelength;
- a third light receiver operated at the second wavelength and positioned between the first and third light emitters, wherein the third light receiver is capable of receiving a fifth amount of light emitted by the first light emitter in the second wavelength and a sixth amount of light emitted by the third light emitter in the second wavelength for further determining the location of the object in the designated interaction area in relation to the first light emitter and the third light emitter based separately on a change in the fifth amount and a change in the sixth amount; and
- a fourth light receiver operated at the second wavelength and positioned between the second and fourth light emitters, wherein the fourth light receiver is capable of receiving a seventh amount of light emitted by the second light emitter in the second wavelength and an eighth amount of light emitted by the fourth light emitter in the second wavelength for further determining the location of the object in the designated interaction area in relation to the second light emitter and the fourth emitter based separately on a change in the seventh amount and a change in the eighth amount.
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Type: Grant
Filed: Aug 13, 2001
Date of Patent: Aug 9, 2005
Patent Publication Number: 20030034439
Assignee: Nokia Mobile Phones Ltd. (Espoo)
Inventors: Gerd Reime (Schomberg), Terho Kaikuranta (Piispanristi)
Primary Examiner: Thanh X. Luu
Attorney: Ware, Fressola, Van Der Sluys & Adolphson LLP
Application Number: 09/928,967